WO2014117484A1

WO2014117484A1 - Prediction method and decoding device for bandwidth expansion band signal

Info

Publication number: WO2014117484A1
Application number: PCT/CN2013/079883
Authority: WO
Inventors: 刘泽新; 苗磊; 齐峰岩
Original assignee: 华为技术有限公司
Priority date: 2013-01-29
Filing date: 2013-07-23
Publication date: 2014-08-07
Also published as: US10388295B2; US20150332688A1; PT3958258T; EP3764354B1; EP3958258A1; EP4451268A3; KR101602264B1; EP3764354C0; CN103971694B; CN103971694A; ES2997082T3; US10607621B2; EP3764354A1; JP6202545B2; US20160247513A1; EP2940685A4; US9875749B2; EP2940685B8; JP2016507781A; US20180122393A1

Abstract

Provided in embodiments of the present invention are a prediction method and decoding device for a bandwidth expansion frequency band signal. The method comprises: demultiplexing a received bitstream to acquire a frequency domain signal; determining whether or not the highest frequency point having bits allocated of the frequency domain signal is less than a predetermined starting frequency of a bandwidth expansion frequency band; if yes, predicting an excitation signal of the bandwidth expansion frequency band on the basis of excitation signals in a predetermined frequency band range of the frequency domain signal and of the predetermined starting frequency point of the bandwidth expansion frequency band; otherwise, predicting the excitation signal of the bandwidth expansion frequency band on the basis of the excitation signals in the predetermined frequency band range of the frequency domain signal, of the predetermined starting frequency point of the bandwidth expansion frequency band, and of the highest frequency point having bits allocated; and, predicting a bandwidth expansion frequency band signal on the basis of the predicted excitation signal of the bandwidth expansion frequency band and of a frequency domain envelope of the bandwidth expansion frequency band. The technical solution of embodiments of the present invention is capable of effectively ensuring between preceding and subsequent frames the continuity of the excitation signals predicted for the bandwidth expansion frequency band signal, thus ensuring the auditory quality of a restored bandwidth expansion frequency band signal.

Description

Prediction method and decoding device for bandwidth extended frequency band signal

This application claims to be filed on January 29, 2013, the Chinese Patent Office, the application number is 201310034240.9, and the invention is entitled "Pressure Method of Bandwidth Extended Band Signal, Decoding Device". The entire contents of the above patents are incorporated by reference. In this application. The present invention relates to the field of communications technologies, and in particular, to a method and a decoding device for predicting a bandwidth extended frequency band signal.

Background technique

In the field of digital communications, voice, image, audio, and video transmissions have a wide range of application requirements, such as mobile phone calls, audio and video conferencing, broadcast television, multimedia entertainment, and the like. In order to reduce the resources occupied during the storage or transmission of audio and video signals, audio and video compression coding technology has emerged. There are many different technical branches in the development of audio and video compression coding technology. The technique of transforming the signal from the time domain to the frequency domain and then performing the coding process is also called transform domain coding technology because of its good compression characteristics. Got a very wide range of applications.

More and more attention is paid to the quality of audio in communication transmission, so it is required to improve the quality of music signals as much as possible while ensuring voice quality. At the same time, due to the extremely rich information of the audio signal, the Code Excited Linear Prediction (CELP) coding mode cannot be used, and the time domain signal is usually converted into the audio coding technology using the transform domain coding. The frequency domain signal processes the audio signal to improve the encoding quality of the audio signal.

In the existing audio coding technology, a fast Fourier transform (hereinafter referred to as FFT) or a modified Discrete Cosine Transform (hereinafter referred to as MDCT) or a discrete cosine transform (Discrete Cosine Transform; A transform technique such as DCT) converts a high-band signal in an audio signal from a time domain signal to a frequency domain signal, and then encodes the frequency domain signal.

Since the limited quantization bits at a low bit rate cannot satisfy all of the audio signals to be quantized, the encoding device uses most of the bits for fine-quantizing the low-band signals in the relatively important audio signals, that is, the quantization parameters of the low-band signals are occupied. Most of the bits; the high frequency band signal in the encoded audio signal is roughly quantized with only a small number of bits, resulting in a frequency domain envelope of the high frequency band signal. The frequency domain envelope of the high frequency band signal and the quantization parameter of the low frequency band signal are then transmitted to the decoding device in the form of a bit stream. Low frequency band signal The quantization parameter may include an excitation signal and a frequency domain envelope. When the low frequency band signal is quantized, the time domain signal may be first converted into a frequency domain signal, and then quantized and encoded as an excitation signal.

The decoding device generally recovers the low frequency band signal according to the quantization parameter of the low frequency band signal in the received bit stream, and then acquires the excitation signal of the low frequency band signal according to the low frequency band signal, and adopts a band width extension; a technique and a spectral filling technique for predicting an excitation signal of a high-band signal based on an excitation signal of a low-band signal, and correcting the excitation signal of the predicted high-band signal according to a frequency domain envelope of the high-band signal in the bitstream The high frequency band signal, the high frequency band signal obtained here is the frequency domain signal.

In the BWE technique, the highest frequency point with bit allocation can be the highest frequency point with the excitation signal, i.e., no excitation signal is decoded from above the frequency point. A frequency band above a highest frequency point having a bit allocation may be referred to as a high frequency band, and a frequency band below a highest frequency point having a bit allocation may be referred to as a low frequency band. The excitation signal of the high frequency band signal is predicted according to the excitation signal of the low frequency band signal, and specifically, the excitation signal of the low frequency band signal below the highest frequency point with the bit allocation is centered on the highest frequency point with bit allocation. A high-band signal that is equal to the bandwidth of the low-band signal above the highest frequency point with the bit allocation is copied as an excitation signal for the high-band signal.

In the process of implementing the present invention, the inventors have found that at least the following problems exist in the prior art: using the above-described prior art prediction bandwidth extension band signal, the excitation signal of the high frequency band signal is predicted according to the excitation signal of the low frequency band signal, between different frames The same high-band signal may be copied on the excitation signals of different low-band signals, causing excitation discontinuity, reducing the quality of the predicted bandwidth extension band signal, thereby reducing the auditory quality of the audio signal.

Summary of the invention

Embodiments of the present invention provide a method for predicting a bandwidth extension band signal and a decoding device for improving the quality of a predicted bandwidth extension band signal, thereby improving the auditory quality of the audio signal.

In a first aspect, an embodiment of the present invention provides a method for predicting a bandwidth extended frequency band signal, including: demultiplexing a received bit stream, and decoding the demultiplexed bit stream to obtain a frequency domain signal; determining the frequency domain Whether the highest frequency point of the signal with bit allocation is smaller than the starting frequency point of the preset bandwidth extension band;

And when the highest frequency point of the bit allocation is smaller than a starting frequency point of the preset bandwidth extension frequency band, the excitation signal in the predetermined frequency band range and the preset bandwidth extension frequency band according to the frequency domain signal The starting frequency point predicts the excitation signal of the bandwidth extension band;

When the highest frequency point of the bit allocation is greater than or equal to the starting frequency point of the preset bandwidth extension frequency band, the excitation signal in the predetermined frequency band range according to the frequency domain signal, the preset bandwidth extension frequency band An initial frequency point and the highest frequency point with bit allocation to predict an excitation signal of the bandwidth extension band;

The bandwidth extended band signal is predicted based on the predicted frequency band excitation signal of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band.

With reference to the first aspect, in a first implementation manner of the first aspect, the excitation of the frequency band in the predetermined frequency band and the initial frequency of the preset bandwidth extension band are used to predict the excitation of the bandwidth extension band Signals, including:

And copying an excitation signal in a predetermined frequency band of the frequency domain signal as an excitation signal between a start frequency point of the preset bandwidth extension frequency band and a highest frequency point of the bandwidth extension frequency band; An integer or non-integer greater than 0, n being equal to the number of frequency points between the starting frequency point of the predetermined bandwidth extension band and the highest frequency point of the bandwidth extension band and the predetermined frequency band of the frequency domain signal The ratio of the number of frequency points.

With reference to the first aspect and the foregoing implementation manner, in a second implementation manner of the first aspect, the n-th excitation signal in the predetermined frequency band of the frequency domain signal is copied as the initial frequency of the preset bandwidth extension frequency band. The excitation signal between the point and the highest frequency point of the bandwidth extension band includes:

Starting from a starting frequency point of the preset bandwidth extension band, sequentially copying an integer number of the frequency domain signals in the n shares to an excitation signal in a predetermined frequency band and a non-integer number in the n parts And an excitation signal in a predetermined frequency band of the frequency domain signal as an excitation signal between a start frequency point of the preset bandwidth extension frequency band and a highest frequency point of the bandwidth extension frequency band; a non-integer number of less than 1 part; or

Starting from the highest frequency point of the bandwidth extension band, sequentially copying the non-integer number of the frequency domain signals in the predetermined frequency band of the n shares to the excitation signal in the predetermined frequency band and the integer number of the n parts And an excitation signal in a predetermined frequency band of the frequency domain signal as an excitation signal between a starting frequency point of the preset bandwidth extension band and a highest frequency point of the bandwidth extension band; a non-integer of the n parts The number of parts is less than 1 part.

With reference to the first aspect, in a third implementation manner of the first aspect, the excitation signal in the predetermined frequency band, the initial frequency point of the preset bandwidth extension band, and the frequency domain signal are determined according to the frequency domain signal The highest frequency point with bit allocation predicts the excitation signal of the bandwidth extension band, including:

Copying from the mth frequency point above the starting frequency point f _{exc start} of the predetermined frequency band range of the frequency domain signal An excitation signal between the end frequency points f _exc — _end of the predetermined frequency band range of the frequency domain signal, and n excitation signals in a predetermined frequency band of the frequency domain signal as the bit allocation of the frequency domain signal An excitation signal between a high frequency point and a highest frequency point of the bandwidth extension band; the n is zero, an integer or non-integer greater than 0, m is the highest frequency point of the bit allocation and a preset The number of frequency points between the starting frequency points of the extended band.

In conjunction with the first aspect and the foregoing implementation manner, in a fourth implementation manner of the first aspect, copying from the f _exc — _start + (the highest frequency point of the bit allocation is one of the preset bandwidth extensions) An initial frequency point of the frequency band)) an excitation signal in the frequency range of the f _exc — _end frequency domain signal, and a frequency range of the frequency domain signal band of the n parts of the f _exc — _start to the f _exc — _end The excitation signal within the excitation signal between the highest frequency point of the bit allocation and the highest frequency point of the bandwidth extension band includes:

Starting from the highest frequency point with bit allocation, sequentially copying from the f _exc — _start + (the highest frequency point of the bit allocation, the starting frequency of the preset bandwidth extension band) An excitation signal in the frequency range of the f _exc — _end frequency domain, the f _exc — _start of an integer number of the n parts to the f _exc — _{∞ (1} in the frequency domain signal band An excitation signal, and a non-integer number of the non-integer fractions of the f _exc — _start to an excitation signal in a frequency domain signal band of the f _exc — _end as a highest frequency point of the bit allocation An excitation signal between the highest frequency points of the bandwidth extension band; a non-integer number of the n parts is less than 1 part; or

Starting from the highest frequency point of the bandwidth extension band, sequentially copying the non-integer number of the f _eXC — start in the n _shares to the excitation signal in the frequency domain signal band of the f _eXC — _end , An excitation signal in the range of the frequency domain signal band of the integer range of the f _exc — _start to the f _exc — ^, and from the f _exc _ _start + (the bit-allocated a frequency point of the highest frequency point of the predetermined bandwidth extension band)) an excitation signal to the frequency range of the f _exc — end frequency domain as the highest frequency point of the bit allocation and the A high-band excitation signal between the highest frequency points of the bandwidth extension band; a non-integer number of the n shares is less than one.

With reference to the first aspect and the foregoing implementation manner, in a fifth implementation manner of the first aspect, before the bandwidth extension band signal is predicted according to the predicted excitation band of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band, The method includes: decoding from the bitstream to obtain a frequency domain envelope of the bandwidth extension band.

With reference to the first aspect and the foregoing implementation manner, in a sixth implementation manner of the first aspect, before the bandwidth extension band signal is predicted according to the predicted excitation band of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band, include: Decoding from the bitstream to obtain a signal type;

A frequency domain envelope of the bandwidth extension band is obtained according to the signal type.

With reference to the first aspect and the foregoing implementation manner, in a seventh implementation manner of the foregoing aspect, the obtaining the frequency domain envelope of the bandwidth extension frequency band according to the signal type includes:

When the signal type is a non-harmonic signal, demultiplexing the received bit stream, and decoding the demultiplexed bit stream to obtain a frequency domain envelope of the bandwidth extension band;

When the signal type is a harmonic signal, demultiplexing the received bit stream, and decoding the demultiplexed bit stream to obtain an initial frequency domain envelope of a bandwidth extension band; and the initial frequency domain envelope The value calculated by weighting the adjacent N initial frequency domain envelopes is used as the frequency domain envelope of the bandwidth extension band, where N is greater than or equal to 1.

In a second aspect, an embodiment of the present invention provides a decoding device, including:

a decoding module, configured to demultiplex the received bit stream, and decode the demultiplexed bit stream to obtain a frequency domain signal;

a determining module, configured to determine whether a highest frequency point of the frequency domain signal having a bit allocation is smaller than a starting frequency point of the preset bandwidth extension frequency band;

a first processing module, configured to: when the determining module determines that a highest frequency point of the bit allocation is smaller than a starting frequency point of the preset bandwidth extension frequency band, according to the frequency domain signal, within a predetermined frequency band An excitation signal and an excitation signal of the bandwidth extension band of the preset frequency band of the preset bandwidth extension band;

a second processing module, configured to: when the determining module determines, when the highest frequency point of the bit allocation is greater than or equal to a starting frequency point of the preset bandwidth extension frequency band, predetermining a frequency band range according to the frequency domain signal An excitation signal, an initial frequency point of the preset bandwidth extension band, and the highest frequency point of the bit allocation to predict an excitation signal of the bandwidth extension band;

And a prediction module, configured to predict a bandwidth extension band signal according to the predicted frequency band excitation band of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band.

With reference to the second aspect, in a first implementation manner of the second aspect, the first processing module is configured to: copy, by using, an excitation signal in a predetermined frequency band of the frequency domain signal as the preset bandwidth extension An excitation signal between a start frequency point of the frequency band and a highest frequency point of the bandwidth extension frequency band; the n is an integer or a non-integer greater than 0, and n is equal to a start frequency point of the preset bandwidth extension frequency band a ratio of the number of frequency points between the highest frequency point of the bandwidth extension band and the number of frequency points in the predetermined frequency band of the frequency domain signal. With reference to the second aspect and the foregoing implementation manner, in a second implementation manner of the second aspect, the first processing module is specifically configured to sequentially start from a starting frequency of the preset bandwidth extension frequency band An excitation signal in a predetermined frequency band of the frequency domain signal and an excitation signal in a predetermined frequency band of the frequency domain signal of the n-part in the n-parts as an integer number of And an excitation signal between a starting frequency point of the bandwidth extension band and a highest frequency point of the bandwidth extension band; the non-integer number of the n parts is less than 1 part; or

The first processing module is specifically configured to sequentially copy, from the highest frequency point of the bandwidth extension frequency band, a non-integer number of the n-number of the frequency domain signals in a predetermined frequency band and an excitation signal An excitation signal in a predetermined frequency band of the frequency domain signal of the integer number of n parts as an excitation between a starting frequency point of the preset bandwidth extension band and a highest frequency point of the bandwidth extension band Signal; a non-integer fraction of the n parts is less than 1 part.

With reference to the second aspect, in a third implementation manner of the second aspect, the second processing module is specifically configured to copy the first frequency point f _exc — _start from a predetermined frequency band of the frequency domain signal An excitation signal between m frequency points to an end frequency point f _exc — _end of a predetermined frequency band range of the frequency domain signal, and n excitation signal signals within a predetermined frequency band of the frequency domain signal as the frequency domain signal An excitation signal between a highest frequency point of the bit allocation and a highest frequency point of the bandwidth extension band; the n is zero, an integer or non-integer greater than 0, and m is the highest frequency point of the bit allocation The value of the frequency point between the frequency of the initial frequency band and the preset extended frequency band.

With reference to the second aspect and the foregoing implementation manner, in a fourth implementation manner of the second aspect, the second processing module is specifically configured to sequentially copy from the highest frequency point of the bit allocation f _exc _ _start + (the highest frequency point of the bit allocation - the starting frequency point of the preset bandwidth extension band)) to the excitation signal in the f _exc - _end frequency domain signal band Said start of the integer part of the n parts to the f _eXC — e. An excitation signal in a frequency domain signal band of d, and said f _exc — _start of a non-integer number of said n parts to said f _exc — _{∞ (1} of an excitation signal in a frequency domain signal band An excitation signal between the highest frequency point of the bit allocation and the highest frequency point of the bandwidth extension band; the non-integer number of the n parts is less than 1 part; or

The second processing module is specifically configured to sequentially copy the non-integer number of the f _exc — _start to the f _exc — ^ from the highest frequency point of the bandwidth extension band. An excitation signal in a frequency domain signal band, an integer number of the n parts of the f _exc — _start to an excitation signal in a frequency domain signal band of the f _exc — _end , and from the f _exc — _start + (the highest frequency point of the bit allocation - the starting frequency of the predetermined bandwidth extension band)) an excitation signal to the signal in the f _{exc en} domain signal band The number is a high-band excitation signal between the highest frequency point of the bit allocation and the highest frequency point of the bandwidth extension band; the non-integer number of the n parts is less than 1 part.

With reference to the second aspect and the foregoing implementation manner, in a fifth implementation manner of the second aspect, the decoding module is further configured to use, in the prediction module, the excitation signal and the bandwidth extension band of the bandwidth extension band that are predicted by the prediction module. The frequency domain envelope predicts the bandwidth extension band signal, and the frequency domain envelope of the bandwidth extension band is obtained by decoding from the bit stream.

With reference to the second aspect and the foregoing implementation manner, in a sixth implementation manner of the second aspect, the method further includes: acquiring the module;

The decoding module is further configured to: before the prediction module predicts the bandwidth extension band of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band, predict a bandwidth extension band signal, and obtain a signal type from the bit stream. ;

The acquiring module is configured to acquire a frequency domain envelope of a bandwidth extension frequency band according to the signal type. With reference to the second aspect and the foregoing implementation manner, in a seventh implementation manner of the second aspect, the acquiring module is specifically configured to: when the signal type is a non-harmonic signal, demultiplex the received bit Streaming, decoding the demultiplexed bitstream to obtain a frequency domain envelope of the bandwidth extension band;

Or the acquiring module is specifically configured to: when the signal type is a harmonic signal, demultiplex the received bit stream, and decode the demultiplexed bit stream to obtain an initial frequency domain packet bandwidth of the bandwidth extended frequency band. The frequency domain envelope of the extended frequency band, where N is greater than or equal to one.

The method for predicting the bandwidth extension band signal and the decoding device in the embodiment of the present invention determine the maximum frequency point and the starting frequency point of the decoded frequency domain signal by setting a starting frequency point of the bandwidth extension. The excitation recovery of the bandwidth extension band is such that the extended excitation signal frames are continuous, and the frequency of the decoded excitation signal is maintained, thereby ensuring the auditory quality of the recovered bandwidth extended frequency band signal, and improving the output. The auditory quality of the audio signal. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art description will be briefly described below, and obviously, the following description will be described below. The drawings in the drawings are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive labor. FIG. 1 is a schematic structural diagram of an encoding device in the prior art.

2 is a schematic structural diagram of a decoding device in the prior art.

FIG. 3 is a flowchart of a method for predicting a bandwidth extended frequency band signal according to an embodiment of the present invention. FIG. 4 is a flowchart of a method for predicting a bandwidth extended frequency band signal according to another embodiment of the present invention. 5a and 5b are schematic diagrams showing frequency bands in an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a decoding device according to an embodiment of the present invention.

FIG. 7 is a schematic structural diagram of a decoding device according to another embodiment of the present invention.

FIG. 8 is a block diagram of a decoding device 80 in accordance with another embodiment of the present invention.

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. The embodiments are a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention. In the field of digital signal processing, audio codecs and video codecs are widely used in various electronic devices, such as: mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers/navigators. , cameras, audio/video players, camcorders, video recorders, surveillance equipment, etc. Generally, such an electronic device includes an audio encoder or an audio decoder, and the audio encoder or decoder can be directly implemented by a digital circuit or a chip such as a DSP ( dig i ta ls igna l proces sor ), or the processor is driven by software code. Implemented by executing the process in the software code. For example, an audio encoder first performs frame processing on the input signal to obtain time domain data of 20 ms-frame; then window processing the time domain data to obtain a windowed signal; and time-domain signal after windowing The frequency domain transform is performed, and the signal is transformed from the time domain to the frequency domain; then the frequency domain signal is encoded and transmitted to the decoding end. After the decoder receives the compressed code stream transmitted by the encoding end, the signal is correspondingly The decoding operation performs inverse transformation corresponding to the transform used by the encoding end of the decoded frequency domain signal, transforms the signal from the frequency domain to the time domain, and performs post-processing on the time domain signal to obtain a synthesized signal, that is, the decoding end output signal.

FIG. 1 is a schematic structural diagram of an encoding device in the prior art. As shown in FIG. 1, the existing coding apparatus includes a time-frequency transform module 10, an envelope extraction module 11, an envelope quantization coding module 12, a bit allocation module 13, an excitation generation module 14, an excitation quantization coding module 15, and multiplexing. Module 16.

As shown in FIG. 1, the time-frequency transform module 10 is configured to receive an input audio signal and then convert the audio signal from a time domain signal to a frequency domain signal. Then, the envelope extraction module 11 extracts a frequency domain envelope from the frequency domain signal transformed by the time-frequency transform module 10, and the frequency domain envelope may also be referred to as a subband normalization factor. The frequency domain envelope here includes the frequency domain envelope of the low frequency band signal in the frequency domain signal and the frequency domain envelope of the high frequency band signal. The envelope quantization coding module 12 performs a quantization coding process on the envelope extraction module 11 to obtain a frequency domain envelope, and obtains a quantized frequency domain envelope. The bit allocation module 13 determines the bit allocation of each subband based on the quantized frequency domain envelope. The excitation generation module 14 normalizes the frequency domain signal obtained by the time-frequency transform module 10 by using the quantized envelope information obtained by the envelope quantization and coding module 12, and obtains an excitation signal, that is, a normalized frequency domain signal. The excitation signal also includes a high frequency band signal excitation signal and a low frequency band signal excitation signal. The excitation quantization coding module 15 performs quantization coding processing on the excitation signal generated by the excitation generation module 14 based on the bit allocation of each sub-band allocated by the bit allocation module 13, to obtain a quantized excitation signal. The multiplexing module 16 multiplexes the quantized frequency domain envelope and the quantized excitation signal of the excitation quantization coding module 15 into a bit stream, which is output to the decoding device.

2 is a schematic structural diagram of a decoding device in the prior art. As shown in FIG. 2, the existing decoding device includes a demultiplexing module 20, a frequency domain envelope decoding module 21, a bit allocation obtaining module 22, an excitation signal decoding module 23, a bandwidth extension module 24, and a frequency domain signal recovery module 25. And frequency time conversion module 26.

As shown in FIG. 2, the demultiplexing module 20 receives the bit stream transmitted by the encoding device side, and decodes the bit stream. Using (including decoding), the quantized frequency domain envelope and the quantized excitation signal are respectively obtained. The frequency domain envelope decoding module 21 obtains the quantized frequency domain envelope from the signal demultiplexed by the demultiplexing module 20, and performs quantization decoding to obtain a frequency domain envelope. The bit allocation acquisition module 22 determines the bit allocation of each sub-band based on the frequency domain envelope obtained by the frequency domain envelope decoding module 21. The excitation signal decoding module 23 obtains the quantized excitation signal from the signal demultiplexed by the demultiplexing module 20, and performs quantization decoding on the bit allocation of each subband obtained by the bit allocation acquisition module 22 to obtain an excitation signal. The bandwidth extension module 24 expands the entire bandwidth according to the excitation signal obtained by the excitation signal decoding module 23, specifically, the excitation signal of the low frequency band signal is used to spread the excitation signal of the high frequency band signal. Since the excitation quantization coding module 15 and the envelope quantization coding module 12 quantize the coded excitation signal and the envelope signal, most of the bits are used to quantize the signals of the relatively important low-band signals, and only a small number of bits are used to quantize the high-frequency signals. The signaled signal may not even include the excitation signal of the high frequency band signal, so the bandwidth extension module 24 needs to spread the excitation signal of the high frequency band signal using the excitation signal of the low frequency band signal to obtain the excitation signal of the entire frequency band. The frequency domain signal recovery module 25 is connected to the frequency domain envelope decoding module 21 and the bandwidth extension module 24, respectively. The frequency domain signal recovery module 25 obtains the entire frequency domain envelope and bandwidth extension module 24 obtained by the frequency domain envelope decoding module 21. The excitation signal of the frequency band recovers the frequency domain signal. The frequency time conversion module 26 converts the frequency domain signal recovered by the frequency domain signal recovery module 25 into a time domain signal, thereby obtaining an original input audio signal.

1 and 2 are structural diagrams of an encoding device and a corresponding decoding device of the prior art. According to the processing procedure of the prior art encoding device and decoding device shown in FIG. 1 and FIG. 2, the excitation signal and envelope of the low-band signal used by the decoding device in recovering the frequency domain signal of the low-band signal in the prior art can be known. The information is transmitted by the encoding device side, so the frequency domain signal recovery of the low frequency band signal is relatively accurate. The frequency domain signal of the high frequency band signal needs to first use the excitation signal of the low frequency band signal to predict the excitation signal of the high frequency band signal, and then correct the predicted high frequency band signal by using the envelope information of the high frequency band signal transmitted by the encoding device side. The excitation signal of the number obtains the frequency domain signal of the high frequency band signal. When the encoding device predicts the frequency domain signal of the high-band signal, the signal type is not considered, and the same frequency domain envelope is used. For example, when the signal type is harmonic, the sub-band range covered by the frequency domain envelope is narrower (less than A harmonic from the peak to the range of the sub-band covered by the trough). When the frequency domain envelope is used to correct the predicted high-band signal excitation, more noise is introduced, so that the error between the modified high-band signal and the real high-band signal is large, which seriously affects Predicting the accuracy of the high-band signal reduces the quality of the predicted high-band signal, thereby reducing the auditory quality of the audio signal. Moreover, in the above prior art, the excitation signal of the high frequency band signal is predicted according to the excitation signal of the low frequency band signal, and the excitation signal of the different low frequency band signal may be copied on the same high frequency band signal between different frames, resulting in no excitation. Continuity reduces the quality of the predicted high-band signal, thereby reducing the auditory quality of the audio signal. Therefore, the technical solutions of the embodiments of the present invention described below can be adopted to solve the above technical problem.

FIG. 3 is a flowchart of a method for predicting a bandwidth extended frequency band signal according to an embodiment of the present invention. The execution body of the prediction method of the bandwidth extension band signal of this embodiment may be a decoding device. As shown in FIG. 3, the method for predicting a bandwidth extension band signal in this embodiment may specifically include the following steps:

100. The decoding device demultiplexes the received bit stream, and decodes the demultiplexed bit stream to obtain a frequency domain signal.

101. The decoding device determines whether the highest frequency point of the bit-domain allocation of the frequency domain signal is smaller than a starting frequency point of the preset bandwidth extension frequency band; when the highest frequency point of the bit allocation is smaller than a starting frequency of the preset bandwidth extension frequency band Point, step 102 is performed; otherwise, when the highest frequency point with bit allocation is greater than or equal to the starting frequency point of the preset bandwidth extension band, step 103 is performed;

102, the decoding device predicts the excitation signal of the bandwidth extension band according to the excitation signal in the predetermined frequency band of the frequency domain signal and the initial frequency band of the preset bandwidth extension band; performing step 104;

103. The decoding device presets a frequency range of the excitation signal according to the frequency domain signal, and presets a bandwidth extension. The starting frequency point of the frequency band and the highest frequency point of the bit allocation are used to predict the excitation signal of the bandwidth extended frequency band; performing step 104;

104. The decoding device predicts the bandwidth extension band signal according to the predicted excitation bandwidth extension band and the frequency domain envelope of the bandwidth extension band.

In the method for predicting the bandwidth extension band signal of the embodiment, by setting a starting frequency point of the bandwidth extension, determining the size of the highest frequency point and the starting frequency point of the decoded frequency domain signal, and performing the bandwidth extension frequency band The excitation recovery is such that the extended excitation signal frames are continuous, and the frequency of the decoded excitation signal is maintained, thereby ensuring the auditory quality of the recovered bandwidth extended frequency band signal, and improving the hearing of the output audio signal. quality.

Optionally, on the basis of the technical solution of the foregoing embodiment, the following extended technical solutions are used to form an extended embodiment of the embodiment shown in FIG. 3. In the extended embodiment, before step 100, Includes the following:

(a) the decoding device receives the bit stream sent by the encoding device; the bit stream carries the quantization parameter of the low frequency band signal and the frequency domain envelope of the bandwidth extended frequency band signal; in this embodiment, the quantization parameter of the low frequency band signal is used to uniquely identify the low frequency band. signal.

(b) The decoding device acquires the excitation signal of the low-band signal according to the quantization parameter of the low-band signal. Specifically, a specific process of the decoding apparatus acquiring the excitation signal of the low frequency band signal according to the quantization parameter of the low frequency band signal may refer to the prior art. For example, when the quantization parameter of the low frequency band signal is the excitation signal of the low frequency band signal and the frequency domain envelope of the low frequency band signal, the decoding device may obtain the excitation signal of the low frequency band signal according to the quantization parameter of the low frequency band signal, and the decoding device may be: The excitation signal of the low-band signal and the frequency domain envelope of the low-band signal recover the low-band signal (where the low-band signal is the frequency-domain signal); then adaptively normalize the low-band signal to obtain the excitation of the low-band signal. signal. When the excitation signal of the bandwidth extension band signal is predicted by using the excitation signal of the low frequency band signal in the quantization parameter, it can be full When the energy requirement of the high-band signal is required, the excitation signal of the bandwidth extension band can be directly predicted by using the excitation signal of the low-band signal in the quantization parameter.

The manner of the adaptive normalization processing described above may be as follows:

1. The decoding device recovers the low frequency band signal by using the quantized parameters of the decoded low frequency band signal (such as the excitation signal of the low frequency band signal and the frequency domain envelope of the low frequency band signal); setting a moving window in the frequency domain coefficient to solve each moving window The average value of the internal frequency domain coefficient amplitude is solved, and the average value of the frequency domain coefficient of the low frequency band signal is solved, and the low frequency band signal (frequency domain signal) is divided by the corresponding average frequency domain coefficient amplitude to obtain the excitation signal of the low frequency band signal. . For example, the low frequency band signal has N1 frequency domain coefficients, and an average value is solved from the first frequency domain coefficient to the tenth frequency domain coefficient, and an average value is solved from the second frequency domain coefficient to the eleventh frequency domain coefficient. Solving an average value from the third frequency domain coefficient to the twelfth frequency domain coefficient, and so on, solving N1 average values; then dividing the N1 low frequency band signals (frequency domain signals) by the corresponding average value, An excitation signal of the low frequency band signal is obtained.

2. The decoding device recovers the low frequency band signal (frequency domain signal) by decoding the quantization parameter of the low frequency band signal (such as the excitation signal of the low frequency band signal and the frequency domain envelope of the low frequency band signal); for the harmonic signal, the adjacent N ( N>1) The frequency domain envelope of the low-band signal is averaged as the envelope of the adjacent N sub-bands, and the frequency domain signals of the adjacent N sub-bands are uniformly divided by the average to obtain the adjacent N sub-bands. With the low-band signal excitation signal, and so on, the excitation signal of the entire low-band signal is obtained; for the non-harmonic signal, the sub-band of each low-band signal is subdivided into M (M>1) small sub-bands, each The small sub-band solves a frequency domain envelope, divides the frequency domain signal of the small sub-band by the frequency domain envelope of the small sub-band obtained, obtains the excitation signal of the small sub-band, and so on, and obtains the entire low-band signal. Excitation signal. The detailed adaptive normalization process can refer to the description of the prior art, and details are not described herein again.

Optionally, in the extended embodiment, before step 104, the method may further include the following: The decoding device decodes the frequency domain envelope of the bandwidth extension band from the bitstream to facilitate execution of step 104. Or optionally, before step 104, the method may further include: decoding the device to obtain a signal type from the bitstream; and acquiring a frequency domain envelope of the bandwidth extension band according to the signal type.

For example, when the signal type is a non-harmonic signal, the decoding device demultiplexes the received bit stream, and decodes the demultiplexed bit stream to obtain a frequency domain envelope of the bandwidth extension band; when the signal type is a harmonic signal The decoding device demultiplexes the received bit stream, and decodes the demultiplexed bit stream to obtain an initial frequency domain envelope of the bandwidth extension band; and the initial frequency domain envelope and the adjacent N initial frequency domains The value obtained by the envelope weighting is taken as the frequency domain envelope of the bandwidth extension band, where N is greater than or equal to 1.

With the prediction method of the bandwidth extension band signal of the above embodiment, the continuity of the bandwidth extension band signal excitation signal predicted before and after the frame can be effectively ensured. This ensures that the recovered bandwidth extends the auditory quality of the band signal, thereby improving the auditory quality of the audio signal.

FIG. 4 is a flowchart of a method for predicting a bandwidth extended frequency band signal according to another embodiment of the present invention. The method for predicting the bandwidth extension band signal of this embodiment is based on the embodiment shown in FIG. 3, and the technical solution of the present invention is described in more detail. The method for predicting the bandwidth extension band signal in this embodiment may specifically include the following content:

200. The decoding device receives the bit stream sent by the encoding device, and decodes the frequency domain signal. The bit stream carries a quantization parameter of the low frequency band signal and a frequency domain envelope of the bandwidth extended frequency band signal. 201. The decoding device acquires an excitation signal of the low frequency band signal according to the quantization parameter of the low frequency band signal.

202. The decoding device determines, according to the quantization parameter of the low frequency band signal, a frequency domain signal having a bit allocation of a highest frequency point f _last

In the present embodiment, f _last — _{sfm is used to} indicate that the frequency domain signal has the highest frequency point of bit allocation.

203. The decoding device determines whether f _last — _sfm is smaller than a starting frequency point fbwe_start of the bandwidth extension band preset by the frequency domain signal. When fiast_sfm 'J is at fbwe_start, performing 204; otherwise, when f _last — _{sfm is} greater than or equal to fbwe_start When performing 205; Referring to the schematic diagram of each frequency point in the frequency band in FIG. 5a and FIG. 5b, the frequency domain signal with bit allocation can be directly decoded, and the bandwidth extension frequency band needs to be predicted by the decoded frequency domain signal: that is, the predetermined frequency domain signal is selected. The excitation signal in the frequency band predicts the excitation signal of the bandwidth extension band. When the magnitude relationship between f _last — _sfm and fbwe — start is different, the extended starting point frequency and the range of the extended signal are different. The shaded portion of the figure indicates the bandwidth range in which the bandwidth extension band needs to be copied from the low frequency band. In Fig. 5a, the start frequency of the preset bandwidth extension band to the highest frequency point of the bandwidth extension band, and there is a bit in Fig. 5b. The highest frequency point assigned to the highest frequency point of the bandwidth extension band. In the case of Fig. 5a, the reproduced excitation signal comprises: n parts of the excitation signal in a predetermined frequency band of the frequency domain signal; in the case of Fig. 5b, the reproduced excitation signal comprises: starting from f _exc — _start + within a predetermined frequency band An excitation signal between the end frequency points f _exc — _end to the predetermined frequency band range, and n excitation signals in a predetermined frequency band range. Where n is an integer greater than 0 or a non-integer.

In this embodiment, f _bwe — _{start is used to} indicate a starting frequency point of a bandwidth extension band preset by the frequency domain signal. The selection of fbwe_start is related to the coding rate (that is, the total number of bits). The higher the coding rate, the higher the starting frequency point f _bwe — _start of the preset bandwidth extension band. For example, for an ultra-wideband signal, when the coding rate is 24 kbpS, the frequency band of the frequency band signal presets the frequency band of the initial frequency band f _bwe — _start =6.4 kHz; at a coding rate of 32 kbps, the frequency bandwidth of the frequency domain signal is preset. The starting frequency of the band f _bwe — _start = 8 kHz.

204, the frequency domain signal decoding apparatus according to the predetermined frequency range f _exc - _start to _f _exc - εηά preset excitation signal and bandwidth extension start frequency band f _bwe - _start prediction bandwidth expansion band excitation signal; performing 206; In this embodiment, the predetermined frequency band range of the frequency domain signal is a predetermined frequency band range from f _exc — _start to f _exc — _end in the low frequency band signal; f _exc — _start is the _start of the bandwidth extension frequency band preset from the frequency domain signal in the low frequency band signal. The frequency point, f _exc — _end is the end frequency of the bandwidth extension band preset from the frequency domain signal in the low frequency band signal, and f _exc — _{end is} greater than f

^A exc_start °

For example, the decoding device can copy n frequency domain signals for a predetermined frequency band range f _exc — _start to f _exc — _end The signal is used as the starting frequency point f _bwe — _{start of the} preset bandwidth extension band and the highest frequency point f _{t of the} bandwidth extension band. The excitation signal between _{P sfm} ; n is an integer or non-integer greater than 0, and n is equal to the starting frequency point f _bwe — _{start of the} preset bandwidth extension band and the highest frequency point f _{t of the} bandwidth extension band. _{The ratio} of the number of frequency points between _{p sfm} and the _ratio of the frequency band of the predetermined frequency band f _exc — _start to f _exc — _end of the frequency domain signal.

For example, in a specific implementation, the decoding device may copy the excitation signal in a predetermined frequency range of the frequency domain signal of the f-portion of f _exc — _star ^Jf _exc — _end from the starting frequency point f _bwe — _{start of the} preset bandwidth extension band. As the starting frequency point f _bwe — start of the preset bandwidth extension band and the highest frequency point f _{t of the} bandwidth extension band. The bandwidth extension band signal between _P and _Sfm , in this embodiment, n may be a positive integer or a decimal, and n is equal to the starting frequency of the preset bandwidth extension band f _bwe — _start and the highest frequency point of the bandwidth extension band f _t . _{The ratio} of the number of frequency points between _{p sfm} and the _ratio of the frequency band of the predetermined frequency band f _exc — _start to f _exc — _end of the frequency domain signal. f _exc — start to f _exc — end The frequency band of the predetermined frequency band is selected according to the signal type and the coding rate. For example, at a lower rate, the relative frequency of the low frequency signal is better for the harmonic signal. For the lower frequency band signal, for the non-harmonic signal, the relatively high frequency band signal with poor relative coding in the low frequency band signal is selected; at the higher rate, the slightly higher frequency band of the low frequency band signal can be selected for the harmonic signal.

The highest frequency point of the bandwidth extension band refers to the highest point of the band that requires the output signal or a specified frequency point. For example, the wideband signal can be 7 kHz or 8 kHz, and the ultra-wideband signal can be 14 kHz or 16 kHz or other preset specific frequency points. .

In this embodiment, the decoding device starts from the starting frequency point f _bwe — _{start of the} preset bandwidth extension frequency band, and copies the excitation signal of the predetermined frequency band of the frequency domain signal of the f-component f _eXC — start to f _eXC — end as a preset. The starting frequency of the bandwidth extension band f _bwe — _start and the highest frequency point f _{t of the} bandwidth extension band. The bandwidth extension band signal between _{p sfm} can be implemented as follows: The decoding device starts from the starting frequency point fbwe_start of the preset bandwidth extension band, and sequentially copies the integer number of f _exc — _{star in} n parts. ^ f _exc — the frequency domain signal of the _end of the frequency band signal in the predetermined frequency band and the non-integer part of the n part of the f _{exc start} to the frequency domain signal of the f _{exc end} The excitation signal in the circumference is used as the starting frequency point f _bwe — _{start of the} preset bandwidth extension band and the highest frequency point f _{t of the} bandwidth extension band. The excitation signal of the bandwidth extension band between _{p sfm} ; the non-integer number of n parts is less than 1 part.

In this embodiment, when the frequency domain signal of the f _exc — _star ^f _exc — _end in the integer part of the n copies is copied, the excitation signal in the predetermined frequency band may be sequentially copied, that is, each time a copy of the f _exc is copied. – the excitation signal in the predetermined frequency band of the frequency domain signal of _start to f _exc — _end until the excitation signal in the predetermined frequency band of the frequency domain signal of n parts of f _exc — _star ^f _exc — _end is copied. Or you can also mirror the copy (or become a copy of the fold), that is, copy the integer number of f _exc — _start to f _exc — _end of the frequency domain signal in the predetermined frequency band of the excitation signal, and then forward copy (ie from f _exc —start to fexc— _end) and an interleaved copy of the reverse copy (ie, from f _exc — end to f _exc — start ) until the N copies are completed.

Or the decoding device can extend the highest frequency point f _t from the preset bandwidth extension band. Starting from _{p sfm} , copying n parts of f _eXC — start to f _eXC — end of the frequency domain signal in the predetermined frequency band of the excitation signal as the starting frequency of the preset bandwidth extension band f _bwe — _start and the bandwidth extension band High frequency point f _t . High band excitation signal between _{p sfm} . Specifically, the method can be implemented as follows: The decoding device extends the highest frequency point f _{t of the} bandwidth from the bandwidth. Starting from _{p sfm} , sequentially copying a non-integer number of f _exc — _star ^f _exc — _{∞ (} the low-band excitation signal in the frequency band of 1 and the f _exc — _start in the integer number of n parts to n f _exc — _end of the frequency domain signal The excitation signal in the predetermined frequency band is used as the starting frequency of the preset bandwidth extension band f _bwe — _start and the highest frequency point of the bandwidth extension band f _t . _p — the bandwidth between _sfm The excitation signal of the extended band; the non-integer number of n parts is less than 1 part.

Specifically, the highest frequency point f _{t of the} bandwidth band is extended from the bandwidth. Starting from _{p sfm} , copying the non-integer number of f _eXC — start to f _eXC — end of the frequency domain signal in the predetermined frequency band of the n shares belongs to a whole block copy, for example, the highest frequency point of the bandwidth extension band is 14kHz, f _exc - _start to f _exc - _enc ^ 1.6kHz to 4kHz, when taking 0.5 parts _f eXC - start to _f eXC - end 1.6kHz to 2.8kHz i.e. low band excitation signal. Using the scheme of this step, the low-band excitation signal of 1.6 kHz to 2.8 kHz can be copied to between (14-1.2) kHz and 14 kHz as the excitation signal of the bandwidth extension band, and the 1.6 kHz corresponding copy is copied to (14-1.2). ) kHz, 2.8kHz pair Should be copied to 14kHz.

In the above two ways, whether from the starting frequency point f _bwe — _{start of the} preset bandwidth extension band or the highest frequency point f _{t of the} bandwidth extension band. p- _sfm start predicting bandwidth extension start frequency band fbwe- start point and the highest frequency bandwidth extension band f _top - the excitation signal bandwidth extension band between _sfm, the final prediction predetermined bandwidth extension band obtained The starting frequency point f _bwe — start and the highest frequency point f _{t of the} bandwidth extension band. The result of the excitation signal of the bandwidth extension band between _{P sfm} is the same.

In the implementation of the foregoing solution, the frequency bandwidth between the starting frequency point f _bwe — start of the preset bandwidth extension band and the highest frequency point f _top ― _sfm of the frequency band signal may be calculated by dividing f _exc — start to The quotient and remainder of the bandwidth between the ends; the quotient here is the integer number of copies in n parts, and the remainder / ( f _exc — _end — f _exc _ _start ) is the non-integer number of n parts. In this manner, the integer number and the non-integer number in the N parts can be calculated first, and then the starting frequency point f _bwe — start of the preset bandwidth extension band and the highest frequency point f _t of the bandwidth extension band are predicted in the above manner. . The excitation signal of the bandwidth extension band between _{p sfm} .

205. The decoding device predicts an excitation signal of a bandwidth extension band according to an excitation signal, fbwe_start, and frast_sfm in a range of f _exc — _start to f _exc — _end ;

For example, the decoding device may copy the excitation from the mth frequency point above the starting frequency point f _exc — _start of the predetermined frequency band of the frequency domain signal to the end frequency f _exc — _{end of the} predetermined frequency band of the frequency domain signal. The signal, and the excitation signal in the predetermined frequency band of the n frequency domain signals are used as the highest frequency point f _last — _{sfm of the} frequency domain signal and the highest frequency point f _{t of the} bandwidth extension band. Excitation signal between _{P sfm} ; n is zero, an integer greater than 0 or a non-integer, m is the highest frequency point with bit allocation f _last — _sfm and the starting frequency of the preset extended band f _bwe — _start The number of frequency points between.

For example, the decoding device can start from the highest frequency point _^^^ with bit allocation, and sequentially copy (f _exc — _start +

(Flast_sfm-fbwe_start)) to f _exc - an excitation signal in the frequency-domain signal in a predetermined frequency range _end of, and n parts _f eXC - start to _f eXC - excitation signals within the excitation band range end of as having bit allocation most High frequency point flast - sfm F _top point of the highest frequency and bandwidth extension band - band excitation signal bandwidth expansion between the _SFM, wherein n is zero, non-integer or integer greater than 0.

In a specific implementation, the decoding device may start from the highest frequency point f _last — _sfm with bit allocation, and sequentially copy the predetermined frequency band range from fexc — _St art+ ( flast — sfm — fbwe — start ) to f _exc — _end frequency domain signal. The internal excitation signal, the integer number of parts in the fraction f _exc — _start to f _exc — _end of the frequency domain signal in the predetermined frequency band of the excitation signal, and n parts of the non-integer number of f _exc — _start to f _{The exc} - _end frequency domain signal has an excitation signal in a predetermined frequency band as the highest frequency point f _last — _sfm with bit allocation and the highest frequency point f _{t of the} bandwidth extension band. The excitation signal of the bandwidth extension band between _{p sfm} ; wherein the non-integer number of n parts is less than 1 part.

Or the decoding device can extend the highest frequency point f _{t of the} bandwidth from the bandwidth. Starting from _{p sfm} , sequentially copy n parts of f _exc — _start to f _exc — _end of the frequency domain signal in the predetermined frequency band of the excitation signal, and from (f _exc — _start + ( flast.sfm -fbwe.start ) ) to f _Exc — _{∞ (} 1 frequency domain signal excitation signal in the predetermined frequency band as the highest frequency point of the bit allocation f _last — _sfm and the highest frequency point of the bandwidth extension band f _t . _p ― _sfm between the bandwidth extension band Excitation signal; for the same reason, where n is zero, an integer greater than 0, or a non-integer.

In a specific implementation, the decoding device can extend the highest frequency point f _{t of the} bandwidth from the bandwidth. Starting from _{p sfm} , sequentially copying the non-integer number of f _exc — _start to f _exc — _end of the n-part frequency domain signal in the predetermined frequency band of the excitation signal, the integer number of n parts of f _exc — _start to f _Exc — the frequency domain signal of the _end frequency band of the excitation signal in the predetermined frequency band, and the excitation signal from the fexc_start+ ( fiast — sfm — e — start ) to the f _exc — _end frequency domain signal within the predetermined frequency band as the highest bit allocation The frequency point f _last — the excitation signal of the bandwidth extension band between the _sfm and the highest frequency point of the bandwidth extension band; wherein the non-integer number of n parts is less than 1 part.

When the decoding device extends the bandwidth from the bandwidth to the highest frequency point f _t . _{p sfm} begins to predict that the frequency domain of the non-integer number of f _exc — _star ^′jf _exc — _end in n copies is also a whole copy, and the frequency domain signal is within a predetermined frequency range. The excitation signal corresponding to the low frequency point is located at the corresponding low frequency point in the bandwidth extension frequency band, and the excitation signal corresponding to the high frequency point in the predetermined frequency band of the frequency domain signal is in the bandwidth The extended frequency band is located at the corresponding high frequency point. For details, refer to the above related description. Similarly, the frequency domain signal of the integer number of f _exc — _star ^′J f _exc — _end in n parts can also be a copy of the excitation signal in a predetermined frequency range, which can also be a sequential copy or a mirror copy. For details, refer to the above correlation. Record, no longer repeat here.

By the above two methods, whether from the highest frequency point f _last — _sfm with bit allocation, or the highest frequency point f _{t of the} bandwidth extension band. _p — _sfm starts to predict the excitation signal of the bandwidth extension band between the highest frequency point f _last — _{stm of the} bit allocation and the highest frequency point of the bandwidth extension band, and finally obtains the highest frequency point f _last with bit allocation – The result of the bandwidth extension band excitation signal between _sfm and the highest frequency point of the bandwidth extension band is the same.

And in the above scheme, when (f _exc — _start + ( flast — sfm — fbwe — start ) ) to f _exc — end the bandwidth is greater than or equal to the highest frequency point of the bit allocation f _last — _sfm and the highest bandwidth extension band When the bandwidth between the frequencies is only needed

( fexc - start + ( flast - sfm fbwe - start ) ) to fexc - end, ( fexc - start + ( flast - sfm fbwe - start ) ) ^ T " , the acquisition bandwidth is equal to the highest frequency point with _last bit allocation f _last - a low band excitation signal bandwidth of the signal with the highest frequency of _sfm point bandwidth extension bit allocation band has a maximum frequency point f _last - excitation bandwidth expansion between the band and the highest frequency point _sfm bandwidth extension band signal.

In the implementation of the above scheme, the acquisition (the highest frequency point f _last — _sfm with bit allocation to the highest frequency point f _t of the frequency band signal can be calculated first. _p — the frequency bandwidth between _sfm and one (f _ex w+ ( flast The difference between .sfm-fbwe.start)) is divided by the frequency quotient between f _exc — _start and f _exc — ^; the quotient here is the integer number of n parts, ^^ / ( fe c end fexc— start ) is a non-integer number of parts in n parts. In this way, the integer number and the non-integer number in the N parts can be calculated first, and then the highest frequency point f _last — _sfm with bit allocation and the highest frequency point of the bandwidth extension band f _top — _sfm are predicted in the above manner. The excitation signal between the bandwidth extension bands.

For example, when the coding rate is 24 kbpS, the starting frequency of the preset bandwidth extension band f _bwe — start

=6.4kHz, ^. ^For! ^. The excitation signal of the bandwidth extension band is predicted as follows: The selected low-band signal extends from 0 to 4 kHz. The Nth frame has the highest frequency point of bit allocation f _last — _sfm

=8kHz, at this time f _last — _sfm > fbwe.start , then adaptively normalize the selected low-band signal excitation signal of 0~4kHz (the specific adaptive normalization process can be detailed) Referring to the description of the above embodiment, no further details are provided herein, and then the excitation signal of the bandwidth extension band of 8 kHz or more is predicted from the normalized low-band signal excitation signal, and the normalized according to the manner of the above embodiment is selected. The sequence of the low-band signal excitation signal is copied: first copy the excitation signal in the predetermined frequency range of the frequency domain signal from 8 kHz to 6.4 kHz, and then copy 0.9 parts of f _exc — _star ^f _exc — _end ( 0~4kHz) The excitation signal in the predetermined frequency range of the frequency domain signal, that is, the excitation signal in the predetermined frequency range of the frequency domain signal of 0 kHz to 3.6 kHz, as the highest frequency point with bit allocation (f _last — _sfm = 8 kHz ) to the highest frequency point f _{t of the} bandwidth extension band. _p — _sfm ( f _t . _p — _sfm = _{14 kHz} ) The excitation signal of the bandwidth extension band. If the N+ _1th frame has the highest frequency point of the bit allocation f _last — _sfm <= 6.4 kHz (the starting frequency of the preset bandwidth extension band fbwe.start = 6.4 kHz), the selected low frequency of 0~4 kHz The signal excitation signal is subjected to adaptive normalization processing, and then the excitation signal of the bandwidth extension band of 6.4 kHz or more is predicted from the normalized low-band signal excitation signal, and the normalization is selected according to the manner of the above embodiment. The order in which the low-band signal excitation signal is copied is as follows: first copy the excitation signal of a predetermined frequency band of the frequency domain signal of f _exc — _start to f _exc — _end ( 0~4 kHz), and then copy 0.9 parts of f _exc — _Start to f _exc — _end ( 0~4 kHz ) of the frequency domain signal in the predetermined frequency band of the excitation signal, as the starting frequency of the preset bandwidth extension band ( f _bwe — _start =6.4kHz ) to the bandwidth extension band High frequency point f _t . _p — _sfm ( f _top _ _sfm = _{14 kHz} ) The excitation signal of the bandwidth extension band.

The highest frequency point of the bandwidth extension band is determined according to the class of the frequency domain signal, for example, when the class of the frequency domain signal is an ultra wideband signal, the highest frequency point f _{t of the} bandwidth extension band. _{p sfm} is 14KHZ. The encoding device and the decoding device usually have determined the class of the frequency domain signal to be transmitted before communicating, so the highest frequency point of the frequency domain signal can be considered as determined.

206. The decoding device expands a frequency band of the excitation signal and the bandwidth extension frequency band according to the predicted bandwidth The envelope predicts the bandwidth extension band signal.

Through the prediction of the excitation signal of the bandwidth extension band signal, it can be found that although the bandwidth extension of the bandwidth extension band signal of the Nth frame and the N+1th frame is different, the excitation signals of the same frequency band above 8 kHz are all from The excitation signals of the same frequency band of the low frequency band signal are predicted, so that continuity between frames can be ensured. The step 206 is then followed to achieve accurate prediction of the bandwidth extended band signal.

With the technical solution of the above embodiment, it is possible to effectively ensure the continuity of the bandwidth-expanded band signal excitation signal before and after the inter-frame prediction. Thereby, the recovered bandwidth extends the auditory quality of the band signal, thereby improving the auditory quality of the audio signal.

A person skilled in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by using hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, and the program is executed when executed. The foregoing steps include the steps of the foregoing method embodiments; and the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

FIG. 6 is a schematic structural diagram of a decoding device according to an embodiment of the present invention. As shown in FIG. 6, the decoding device of this embodiment includes a decoding module 30, a determining module 31, a first processing module 32, a second processing module 33, and a prediction module 34.

The decoding module 30 is configured to demultiplex the received bit stream, and obtain a frequency domain signal. The determining module 31 is connected to the decoding module 30, and the determining module 31 is configured to determine that the frequency domain signal decoded by the decoding module 30 has the most bit allocation. Whether the high frequency point is smaller than the starting frequency point of the preset bandwidth extension frequency band; the first processing module 32 is connected to the determining module 31, and the first processing module 32 is configured to determine that the highest frequency point of the bit allocation is less than the pre-determination When the bandwidth of the bandwidth extension band is set, the excitation signal of the bandwidth extension band is predicted according to the excitation signal in the predetermined frequency band of the frequency domain signal and the initial frequency band of the preset bandwidth extension band; the second processing module 33 also The judging module 31 is connected, and the second processing module 33 is used to judge the module 31. Determining that when the highest frequency point of the bit allocation is greater than or equal to the starting frequency point of the preset bandwidth extension frequency band, the excitation frequency signal in the predetermined frequency band according to the frequency domain signal, the starting frequency point of the preset bandwidth extension frequency band, and The highest frequency point of the bit allocation predicts the excitation signal of the bandwidth extension band; the prediction module 34 is connected to the first processing module 32 or the second processing module 33, and when the determining module 31 determines that the highest frequency point of the bit allocation is less than the preset bandwidth The prediction module 34 is coupled to the first processing module 32 when the starting frequency of the frequency band is extended. When the judging module 31 determines that the highest frequency point of the bit allocation is greater than or equal to the starting frequency point of the preset bandwidth extension band, the prediction module 14 is connected to the second processing module 33. The prediction module 34 is configured to be based on the first processing module

32 or the second processing module 33 predicts the bandwidth extension band excitation signal and the bandwidth extension band frequency domain envelope prediction bandwidth extension band signal.

The decoding device of the present embodiment, the prediction of the bandwidth extension band signal by using the foregoing module is the same as the implementation process of the foregoing related method embodiment. For details, reference may be made to the description of the related method embodiment, and details are not described herein again.

The decoding device of this embodiment implements the bandwidth extension band by determining the starting point of a bandwidth extension by using the above-mentioned module, and determining the size of the highest frequency point and the starting frequency point of the decoded frequency domain signal. The excitation recovery is such that the extended excitation signal frames are continuous, and the frequency of the decoded excitation signal is maintained, thereby ensuring the auditory quality of the recovered bandwidth extended frequency band signal, and improving the hearing of the output audio signal. quality. .

FIG. 7 is a schematic structural diagram of a decoding device according to another embodiment of the present invention. As shown in FIG. 7, the decoding apparatus of this embodiment further introduces the technical solution of the present invention in more detail on the basis of the above-described embodiment shown in FIG. 6.

As shown in FIG. 7, the first processing module 32 is specifically configured to copy an excitation signal in a predetermined frequency band of n frequency domain signals as a starting frequency point of a preset bandwidth extension frequency band and a highest frequency point of a bandwidth extension frequency band. Excitation signal; n is an integer greater than 0 or a non-integer, n is equal to the starting frequency of the preset bandwidth extension band The ratio of the number of frequency points between the point and the highest frequency point of the bandwidth extension band and the number of frequency points in the predetermined frequency band of the frequency domain signal.

Further, the first processing module 32 in the decoding device of the embodiment is specifically configured to sequentially copy a predetermined frequency range of the frequency domain signal of the integer number of copies in the n-part from the starting frequency of the preset bandwidth extension band. The excitation signal within the predetermined frequency band of the excitation signal and the non-integer number of frequency domain signals in n parts is used as an excitation signal between the initial frequency point of the preset bandwidth extension band and the highest frequency point of the bandwidth extension band The non-integer number of n parts is less than 1 part; or the first processing module 32 is specifically configured to sequentially copy a non-integer number of frequency domain signals in n parts from a highest frequency point of the bandwidth extension band to a predetermined frequency band range. The excitation signal in the predetermined frequency band of the excitation signal and the integer number of frequency domain signals in n parts is used as an excitation signal between a starting frequency point of the preset bandwidth extension band and a highest frequency point of the bandwidth extension band; The non-integer fraction in n parts is less than 1 part.

Optionally, the second processing module 33 in the decoding device of the embodiment is specifically configured to copy the frequency from the mth frequency point above the starting frequency point f _exc — _start of the predetermined frequency band of the frequency domain signal to the frequency domain signal. The excitation signal between the end frequency points f _exc — _end of the frequency band range, and the excitation signal in the predetermined frequency band range of the n frequency domain signals as the highest frequency point of the bit-domain distribution of the frequency domain signal and the highest frequency point of the bandwidth extension band The excitation signal between; _n is an integer greater than 0 or a non-integer, and m is the number of frequency points between the highest frequency point with bit allocation and the starting frequency point of the preset extended frequency band.

Further optionally, the second processing module 33 in the decoding device of the embodiment is specifically configured to start from the highest frequency point with bit allocation, and sequentially copy from f _exc — _start + (the highest frequency point with bit allocation is one pre- Set the starting frequency of the bandwidth extension band)). - the excitation signal in the frequency domain signal band _end of the range, said integer number of copies of parts of n f _exc - _start to f _exc - an excitation signal in the frequency domain signal of the frequency band _end, and parts of non-integer parts of n Excitation signal in the frequency domain signal band of the number f _exc — _start to f _exc — _end as the excitation signal between the highest frequency point with bit allocation and the highest frequency point of the bandwidth extension band; Integer number is less than 1 part; or the second processing mode 13 is specifically used to sequentially copy the non-integer number of f _exc — _start to f _exc — _end in the frequency domain signal band range of n parts from the highest frequency point of the bandwidth extension band The excitation signal, the integer fraction of n parts of f _exc — _start to f _exc — _end of the excitation signal in the frequency domain signal band, and from f _exc — _start + (the highest frequency point with bit allocation The initial frequency of the bandwidth extension band)) to the _excc - _end frequency domain signal band of the excitation signal as the high frequency band between the highest frequency point with bit allocation and the highest frequency point of the bandwidth extension band Excitation signal; the number of non-integer parts in n parts is less than 1 part.

Optionally, the decoding module 30 of this embodiment is further configured to: after the prediction module 34 predicts the bandwidth extension band signal according to the predicted bandwidth extension band excitation signal and the bandwidth extension band frequency band envelope, the bandwidth is decoded from the bit stream. The frequency domain envelope of the extended frequency band, the corresponding prediction module 34 is also connected to the decoding module 30, and the prediction module 34 is configured to use the bandwidth extension band excitation signal and the decoding module according to the first processing module 32 or the second processing module 33. The frequency domain envelope of the bandwidth extension band obtained by decoding 30 predicts the bandwidth extension band signal.

Further, optionally, the decoding device of this embodiment further includes an obtaining module 35.

The decoding module 30 is further configured to: after the prediction module 34 predicts the bandwidth extension band signal according to the predicted bandwidth extension band excitation band and the bandwidth extension band frequency band envelope, the signal type is obtained from the bit stream; the obtaining module 35 and the decoding module The 30 connection, obtaining module 35 is configured to obtain a frequency domain envelope of the bandwidth extension band according to the signal type decoded by the decoding module 30. At this time, the corresponding prediction module 34 is connected to the acquisition module 35, and the prediction module 34 is configured to use the excitation signal of the bandwidth extension band predicted by the first processing module 32 or the second processing module 33 and the frequency domain of the bandwidth extension band obtained by the acquisition module 35. The envelope predicts the bandwidth extension band signal.

Further, optionally, the obtaining module 35 is specifically configured to: when the decoding module 30 decodes the signal type into a non-harmonic signal, demultiplex the received bit stream, and obtain a frequency domain envelope of the bandwidth extension band; or obtain The module 35 is specifically configured to: when the decoding module 30 decodes the signal type into a harmonic signal, The received bit stream is demultiplexed, and the initial frequency domain envelope of the bandwidth extension band is decoded. The value obtained by weighting the initial frequency domain envelope and the adjacent N initial frequency domain envelopes is used as the frequency of the bandwidth extension band. Domain envelope, where N is greater than or equal to 1.

The decoding device of the foregoing embodiment is described by using all the optional technical solutions described above as an example. In an actual application, all the foregoing optional technical solutions may be combined in any combination to form an optional embodiment of the present invention. This will not be repeated here.

The decoding device of the foregoing embodiment implements the prediction of the bandwidth extension band signal by using the foregoing module. The implementation process of the foregoing related method embodiment is the same as the description of the related method embodiment, and details are not described herein again.

The encoding device of the above embodiment implements the bandwidth extension band by determining the starting point of a bandwidth extension by using the above-mentioned module, and determining the size of the highest frequency point and the starting frequency point of the decoded frequency domain signal. The excitation recovery is such that the extended excitation signal frames are continuous, and the frequency of the decoded excitation signal is maintained, thereby ensuring the auditory quality of the recovered bandwidth extended frequency band signal, and improving the hearing of the output audio signal. quality.

The function of the decoding device shown in FIG. 2 can be adjusted according to the foregoing function module, and an example of the decoding device in the embodiment of the present invention is obtained, and details are not described herein again.

The decoding device of the embodiment of the present invention can be used together with the existing encoding device shown in FIG. 1 to form a prediction system for a bandwidth extended frequency band signal, which is not described herein again.

FIG. 8 is a block diagram of a decoding device 80 in accordance with another embodiment of the present invention. The decoding device 80 of FIG. 8 can be used to implement the steps and methods in the foregoing method embodiments. The decoding device 80 can be applied to a base station or a terminal in various communication systems. In the embodiment of FIG. 8, decoding device 80 includes a receiving circuit 802, a decoding processor 803, a processing unit 804, a memory 805, and an antenna 801. The processing unit 804 controls the operation of the decoding device 80, which may also be referred to as a CPU (Central Processing Unit). Storage The 805 can include read only memory and random access memory and provides instructions and data to the processing unit 804. A portion of the memory 805 may also include non-volatile line random access memory (NVRAM). In a particular application, decoding device 80 may embed or itself be a wireless communication device such as a mobile telephone, and may also include a carrier that houses receiving circuitry 801 to allow decoding device 80 to receive data from a remote location. Receive circuit 801 can be coupled to antenna 801. The various components of decoding device 80 are coupled together by a bus system 806, which in addition to the data bus includes a power bus, a control bus, and a status signal bus. However, for clarity of description, various buses are labeled as bus system 806 in FIG. The decoding device 80 may also include a processing unit 804 for processing signals, and further includes a decoding processor 803.

The method disclosed in the foregoing embodiment of the present invention may be applied to the decoding processor 803 or implemented by the decoding processor 803. Decoding processor 803 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the foregoing method embodiment may be completed by decoding an integrated logic circuit of hardware in the processor 803 or an instruction in a form of software. These instructions can be implemented and controlled by processing unit 804. The above decoding processor may be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, and a discrete Hardware components. The methods, steps, and logical block diagrams disclosed in the embodiments of the present invention may be implemented or executed. The general purpose processor may be a microprocessor, or the processor may be any conventional processor, decoder or the like. The steps of the method disclosed in connection with the embodiments of the present invention may be directly performed by a decoding processor embodied as hardware, or performed by a combination of hardware and software modules in the decoding processor. The software modules can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The storage medium is located in the memory 805, and the decoding processor 803 reads the information in the memory 805 and combines the hardware to complete the steps of the above method. For example, the signal decoding device of FIG. 6 or FIG. 7 can be implemented by the decoding processor 803. In addition, the decoding module 30, the determining module 31, the first processing module 32, the second processing module 33, and the prediction module 34 in FIG. 6 may be implemented by the processing unit 804, or may be implemented by the decoding processor 803. Similarly, the various modules in FIG. 7 may be implemented by the processing unit 804 or by the decoding processor 803. However, the above example is merely specific. The memory 805 stores instructions for causing the processor 804, or the decoding processor 803 to: demultiplex the received bit stream, decode the obtained frequency domain signal; and determine that the frequency domain signal has bits. Whether the allocated highest frequency point is smaller than a starting frequency point of the preset bandwidth extension frequency band; when the highest frequency point having the bit allocation is smaller than the starting frequency point of the preset bandwidth extension frequency band, according to the An excitation signal in a predetermined frequency band of the frequency domain signal and an excitation signal of the initial frequency point of the predetermined bandwidth extension band to predict a bandwidth extension band; when the highest frequency point of the bit allocation is greater than or equal to the preset And an excitation signal in a predetermined frequency band, a starting frequency point of the preset bandwidth extension band, and the highest frequency point prediction station with the bit allocation according to the frequency band of the frequency band. An excitation signal of the bandwidth extension band; predicting the bandwidth extension band signal according to the predicted frequency band excitation signal of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band.

The device embodiments described above are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, ie may be located in one place. , or it can be distributed to at least two network elements. Some or all of the modules may be selected according to actual needs to achieve the objectives of the solution of the embodiment. Those of ordinary skill in the art can understand and implement without deliberate labor.

It should be noted that the above embodiments are only for explaining the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: Modifying the technical solutions described in the foregoing embodiments, or The technical features of the present invention are not limited to the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

Rights request

1. A prediction method for bandwidth extension frequency band signals, which is characterized by including:

Demultiplex the received bit stream, decode the demultiplexed bit stream to obtain a frequency domain signal; determine whether the highest frequency point of the frequency domain signal with bit allocation is less than the starting frequency of the preset bandwidth extension band point;

When the highest frequency point with bit allocation is less than the starting frequency point of the preset bandwidth extension frequency band, according to the excitation signal within the predetermined frequency band range of the frequency domain signal and the preset bandwidth extension frequency band Start frequency point prediction bandwidth extension band excitation signal;

When the highest frequency point with bit allocation is greater than or equal to the starting frequency point of the preset bandwidth extension frequency band, the excitation signal within the predetermined frequency band range of the frequency domain signal, the preset bandwidth extension frequency band The starting frequency point and the highest frequency point with bit allocation predict the excitation signal of the bandwidth extension frequency band;

The bandwidth extension band signal is predicted based on the predicted excitation signal of the bandwidth extension frequency band and the frequency domain envelope of the bandwidth extension frequency band.

2. The method according to claim 1, characterized in that: predicting the excitation signal of the bandwidth extension band based on the excitation signal within the predetermined frequency band range of the frequency domain signal and the starting frequency point of the preset bandwidth extension frequency band, include:

Copy n copies of the excitation signal within the predetermined frequency band range of the frequency domain signal as the excitation signal between the starting frequency point of the preset bandwidth extension frequency band and the highest frequency point of the bandwidth extension frequency band; the n is An integer or non-integer greater than 0, n is equal to the number of frequency points between the starting frequency point of the preset bandwidth extension frequency band and the highest frequency point of the bandwidth extension frequency band and within the predetermined frequency band range of the frequency domain signal The ratio of the number of frequency points.

3. The method according to claim 2, characterized in that, n copies of the excitation signal within the predetermined frequency band range of the frequency domain signal are used as the starting frequency point of the preset bandwidth extension frequency band and the bandwidth extension frequency band. The excitation signal between the highest frequency points includes:

Starting from the starting frequency point of the preset bandwidth extension frequency band, sequentially copy the excitation signal within the predetermined frequency band range of the integer number of the n parts and the non-integer parts of the n parts. The excitation signals within the predetermined frequency band range of several frequency domain signals are used as the excitation signals between the starting frequency point of the preset bandwidth extension frequency band and the highest frequency point of the bandwidth extension frequency band; among the n portions The non-integer number of copies is less than 1; or Starting from the highest frequency point of the bandwidth extension frequency band, sequentially copy the excitation signal within the predetermined frequency band range of the non-integer number of the n portions of the frequency domain signal and all the integer portions of the n portions. The excitation signal within the predetermined frequency band range of the frequency domain signal is used as the excitation signal between the starting frequency point of the preset bandwidth extension frequency band and the highest frequency point of the bandwidth extension frequency band; a non-integer number in the n parts The number of servings is less than 1 serving.

4. The method according to any one of claims 1 to 3, characterized in that, according to the excitation signal within the predetermined frequency band range of the frequency domain signal, the starting frequency point of the preset bandwidth extension frequency band and the frequency The highest frequency point of the domain signal with bit allocation predicts the excitation signal of the bandwidth extension band, including:

Copy from the mth frequency point f _exc — _start above the starting frequency point f _exc — _start of the predetermined frequency band range of the frequency domain signal to the end frequency point f _exc — _end of the predetermined frequency band range of the frequency domain signal. The excitation signal between n parts of the frequency domain signal within the predetermined frequency band range is used as the excitation between the highest frequency point of the frequency domain signal with bit allocation and the highest frequency point of the bandwidth extension frequency band. signal; _{the n} is zero, an integer greater than 0 or a non-integer, m is a positive integer, m is equal to the number of frequency points between the highest frequency point with bit allocation and the preset starting frequency point of the extended frequency band value.

5. The method according to claim 4, characterized in that, copying starts from the mth frequency point f _exc — _{start above the starting frequency point f exc — start} of the predetermined frequency band range of the frequency domain signal to the starting frequency point f _exc — _start + The excitation signal between the end frequency points f _exc - _end of the predetermined frequency band range of the frequency domain signal, and n excitation signals within the predetermined frequency band range of the frequency domain signal are used as the highest frequency point with bit allocation for the frequency domain signal. The excitation signal between the highest frequency point of the bandwidth extension band includes:

Starting from the highest frequency point with bit allocation, sequentially copy the excitation signal of the low-frequency band signal starting from the f _exc — _start + and ending at the f _exc — _end , and the integer number of n copies. The excitation signal of the low-frequency band signal between the f _exc — _start and the f _exc — end, and the non-integer number of the n parts between the f _exc — _start and the f _exc — end The excitation signal of the low-frequency band signal is used as the excitation signal between the highest frequency point with bit allocation and the highest frequency point of the bandwidth extension frequency band; the non-integer number in the n parts is less than 1 part; or

Starting from the highest frequency point of the bandwidth extension frequency band, sequentially copy the non-integer number of excitation signals of the low-frequency band signal between the f _exc — start and _{the end} in the n parts, and the n parts The excitation signal of the low-frequency band signal between the fexc_start and the fexc_end is an integer number, and the excitation of the low-frequency band signal from the _{fexc_start} + to the _{fexc_end} The signal is used as a high-frequency band excitation signal between the highest frequency point with bit allocation and the highest frequency point of the bandwidth extension frequency band; the non-integer number of the n parts is less than 1 part.

6. The method according to any one of claims 1 to 5, characterized in that: according to the predicted bandwidth expansion The excitation signal of the spread band and the frequency domain envelope of the bandwidth extension band are also included before predicting the bandwidth extension band signal:

The frequency domain envelope of the bandwidth extension band is obtained by decoding from the bit stream.

7. The method according to any one of claims 1 to 5, characterized in that, before predicting the bandwidth extension band signal based on the predicted excitation signal of the bandwidth extension band and the frequency domain envelope of the bandwidth extension band, it further includes:

Decoding from the bit stream to obtain a signal type;

Obtain the frequency domain envelope of the bandwidth extension band according to the signal type.

8. The method according to claim 7, characterized in that, obtaining the frequency domain envelope of the bandwidth extension band according to the signal type includes:

When the signal type is a non-harmonic signal, demultiplex the received bit stream, and decode the demultiplexed bit stream to obtain the frequency domain envelope of the bandwidth extension band;

When the signal type is a harmonic signal, demultiplex the received bit stream, and decode the demultiplexed bit stream to obtain an initial frequency domain envelope of the bandwidth extension band; The value calculated by weighting with adjacent N initial frequency domain envelopes is used as the frequency domain envelope of the bandwidth extension frequency band, where N is greater than or equal to 1.

9. A decoding device, characterized by including:

A decoding module, used to demultiplex the received bit stream, and decode the demultiplexed bit stream to obtain a frequency domain signal;

A judgment module, used to judge whether the highest frequency point of the frequency domain signal with bit allocation is less than the starting frequency point of the preset bandwidth extension frequency band;

The first processing module is configured to: when the judgment module determines that the highest frequency point with bit allocation is less than the starting frequency point of the preset bandwidth extension frequency band, according to the frequency domain signal within the predetermined frequency band range The excitation signal and the starting frequency point of the preset bandwidth extension frequency band predict the excitation signal of the bandwidth extension frequency band;

The second processing module is configured to predetermine a frequency band range according to the frequency domain signal when the judgment module determines that the highest frequency point with bit allocation is greater than or equal to the starting frequency point of the preset bandwidth extension frequency band. Predict the excitation signal of the bandwidth extension band based on the excitation signal within the preset bandwidth extension band, the starting frequency point of the preset bandwidth extension frequency band, and the highest frequency point with bit allocation;

A prediction module, configured to predict a bandwidth extension frequency band signal based on the predicted excitation signal of the bandwidth extension frequency band and the frequency domain envelope of the bandwidth extension frequency band.

10. The device according to claim 9, characterized in that, the first processing module is specifically configured to copy n copies of the excitation signal within the predetermined frequency band range of the frequency domain signal as the preset bandwidth extension frequency band. The excitation signal between the starting frequency point and the highest frequency point of the bandwidth extension frequency band; The n is an integer or non-integer greater than 0, and n is equal to the starting frequency point of the preset bandwidth extension frequency band and the The ratio of the number of frequency points between the highest frequency points of the bandwidth extension frequency band to the number of frequency points within the predetermined frequency band range of the frequency domain signal.

11. The device according to claim 10, wherein the first processing module is specifically configured to copy the integers in the n copies sequentially starting from the starting frequency point of the preset bandwidth extension band. The excitation signals within the predetermined frequency band range of the frequency domain signal and the excitation signals within the predetermined frequency band range of the non-integer parts of the frequency domain signal in the n parts are used as the starting point of the preset bandwidth extension frequency band. The excitation signal between the starting frequency point and the highest frequency point of the bandwidth extension frequency band; the non-integer number of n parts is less than 1 part; or

The first processing module is specifically configured to sequentially copy, starting from the highest frequency point of the bandwidth extension band, non-integer copies of the n copies of the excitation signal within the predetermined frequency band range of the frequency domain signal and the The excitation signals within the predetermined frequency band range of the frequency domain signal in the n parts are used as the excitation between the starting frequency point of the preset bandwidth extension frequency band and the highest frequency point of the bandwidth extension frequency band. Signal; The non-integer number of n parts is less than 1 part.

12. The device according to any one of claims 9-11, characterized in that the second processing module is specifically used to copy the starting frequency point f _exc — _start from the predetermined frequency band range of the frequency domain signal. The excitation signal between the mth frequency point f _exc — _start + the start and the end frequency point f _exc — _end of the predetermined frequency band range of the frequency domain signal, and n excitation signals within the predetermined frequency band range of the frequency domain signal As the frequency domain signal, there is an excitation signal between the highest frequency point of bit allocation and the highest frequency point of the bandwidth extension frequency band; the n is zero, an integer greater than 0 or a non-integer, m is a positive integer, m is equal to the number of frequency points between the highest frequency point with bit allocation and the preset starting frequency point of the extended frequency band.

_13. The device according to claim 12, characterized in that the second processing module is specifically configured to copy, starting from the highest frequency point with bit allocation, sequentially starting from the f _{exc_start} + to The excitation signal at the end of the f _exc — _end , the integer number of excitation signals between the f _exc — _start and the f _exc — _end among the n parts, and the non-integer parts among the n parts The excitation signal between the f _exc — _start and the f _exc — _end of the number is used as the excitation signal between the highest frequency point with bit allocation and the highest frequency point of the bandwidth extension frequency band; The number of non-integer copies in n is less than 1; or

The second processing module is specifically configured to start from the highest frequency point of the bandwidth extension band, in order Copy the excitation signal between the f _exc — _start and the f _exc — _end of the non-integer number of the n parts, and the f _exc — _start of the integer number of the n parts. The excitation signal between _end , and the excitation signal from f _exc — _start + to the end of f _exc — _end are used as the highest frequency point with bit allocation and the highest frequency point of the bandwidth extension frequency band The high-frequency band excitation signal between; the non-integer number of n parts is less than 1 part.

14. The device according to any one of claims 9 to 13, characterized in that, the decoding module is also configured to predict the excitation signal of the bandwidth extension frequency band and the frequency domain of the bandwidth extension frequency band in the prediction module. Before the envelope predicts the bandwidth extension frequency band signal, the frequency domain envelope of the bandwidth extension frequency band is obtained by decoding from the bit stream.

15. The device according to any one of claims 9 to 14, further comprising: an acquisition module; the decoding module, further configured to: in the prediction module, according to the predicted excitation signal and bandwidth of the bandwidth extension band Before the frequency domain envelope prediction bandwidth of the extended frequency band extends the frequency band signal, the signal type is obtained by decoding from the bit stream;

The acquisition module is configured to acquire the frequency domain envelope of the bandwidth extension band according to the signal type.

16. The device according to claim 15, characterized in that the acquisition module is specifically used to demultiplex the received bit stream when the signal type is a non-harmonic signal. Decode the bit stream to obtain the frequency domain envelope of the bandwidth extension band;

Or the acquisition module is specifically configured to demultiplex the received bit stream when the signal type is a harmonic signal, and decode the demultiplexed bit stream to obtain the initial frequency domain packet bandwidth of the bandwidth extension band. Frequency domain envelope of the extended frequency band, where N is greater than or equal to 1.